London -LRB- CNN -RRB- -- Six people were arrested Wednesday in what London 's Metropolitan Police is calling a separate phone-hacking conspiracy at Rupert Murdoch 's defunct News of the World newspaper .

All of them are journalists or former journalists , police said .

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Dozens of people , including Murdoch protÃ © gÃ © Rebekah Brooks and Andy Coulson , a former adviser to prime Minister David Cameron , already have been arrested and several have been charged with phone hacking and related crimes .

Police say Wednesday 's arrests are part of a separate conspiracy to hack phones , primarily from 2005 to 2006 , at the News of the World .

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Three men and two women were arrested in London and one woman in Cheshire , in northern England .

Searches are being carried out at several addresses , police said .

`` In due course officers will be making contact with people they believe have been victims of the suspected voicemail interceptions , '' a police statement said .

Murdoch closed the Sunday tabloid , one of the world 's best-selling English-language newspapers , in 2011 over the phone-hacking scandal .

Three police investigations were created to look into allegations of phone hacking , bribery of public officials and computer hacking .

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Brooks and Coulson are both former News of the World editors . Brooks later became chief executive of News International , a UK subsidiary of Murdoch 's News Corp. empire . Coulson went on to become Cameron 's director of communications before resigning early in 2011 .

The hacking scandal prompted Cameron to set up an independent , judge-led inquiry -- named for Lord Justice Leveson , its chairman -- to make recommendations on journalistic ethics and examine the relationship of the press with the public , police and politicians .

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NEW : Six current or former journalists are arrested in connection with alleged phone hacking

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Police say the alleged phone-hacking conspiracy is separate from one already being probed

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London 's Metropolitan Police is running three investigations into alleged wrongdoing

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Rupert Murdoch shut down the News of the World after the scandal broke in 2011